1. The Field of the Invention
The field of the invention relates to a stitch controller for installation on an electric sewing machine with a treadle and a needle positioner. The controller has a central processing unit which defines a stitch procedure as a defined number of runs of stitches and a defined number of stitches in each run.
2. Description of the Prior Art
The prior art of interest is set forth in U.S. Pat. Nos. 4,732,095 (Mar., 1988 to Saito et al); 4,555,997 (Dec., 1985 to Tancs); 4,369,722 (Jan., 1983 to Nishida et al); and 4,195,582 (Apr., 1980 to Novick et al). Saito, Nishida and Novick all utilize a central processing unit to control sewing operations of various kinds. Tancs utilizes an array of detectors and switches. The others in some fashion utilize the presence of a needle positioner to provide information ancillary to the sewing operation. None appears to utilize the needle positioner itself as the sole means by which semi-automatic sewing operations are controlled. Both complex electric, electronic and logic circuits are required to provide the desired control of sewing operations. None is adaptable to a self-containing package containing a central processing unit (CPU) which is readily installed on any manually operated commercial sewing machine with a needle positioner and a treadle so as to make it semi-automatic.